1. Field of the Invention
This invention relates to a folding (collapsible) fire-escape ladder of metal which, in the normal state, is folded, and thus burglar proof but which, in the event of fire, can be unfolded by a simple manual operation from each escape station to form a fire-escape ladder which reaches right down to the ground and which is equipped with guides for brackets and safety belts.
The safety belt is secured to one of the ladder side rails by means of its locking bracket. These brackets are so designed that, when unloaded, they slide down the side rail but, when loaded with the weight of a person (irrespective of size) they lock onto the side rail, thus preventing the person from falling off the ladder.
As will be known, certain safety requirements are demanded in connection with fire-escape routes for houses with two or more stories. This problem is often solved by such means as fire-escape ropes, rope ladders, or a robust ladder with safety hoops permanently fixed on the outside of the building.
Rope climbing requires training, and it is too late to consider this aspect once a fire has started. Climbing on a swinging rope ladder requires good physical condition and also strong nerves, while the safety of permanently fixed fire-escape ladders, with safety hoops, can be open to question, should a person, in a state of panic, lose a handhold or foothold. In such instances, there is a real risk of falling down through the ladder, as in a shaft. Furthermore, such ladders are eyesores on house fronts.
2. Description of the Prior Art
Various types of fire escape ladders are known.
The ladder described in U.S. Pat. No. 4,245,717 is made in separate sections for each floor of a building. In an escape situation, the occupant of the upper floor of the house must first release his own ladder section. When he has climbed out onto this section he must then release the ladder section in the floor below. This he does either by bending down while holding fast with one hand, to release the next ladder section, or he searches with his foot to find the release device.
This is the manner in which the escaping person must proceed, floor by floor, or ladder section by ladder section. It is obvious that such a descent is risky, and particularly so if it is dark and the person has to fumble around to find the release device at each floor. Further, this ladder has several cross struts between the steps which must impede descent. In addition, the ladder has no safety arrangement to prevent falling should a person lose one's handhold or foothold.
U.S. Pat. No. 3,414,081 describes a collapsible ladder with a release arrangement at the top of the ladder. To this release arrangement there is fixed a cord. If the ladder is to be used by the occupants of a house with several floors, it must be possible for the occupants of all the floors to reach this cord. As a result, the ladder is no longer burglar proof. If the cord were to be removed, the ladder would not be of any use as an escape route for houses with several floors should the occupant of the top floor not be at home or should find it impossible to release the ladder in the event of fire. Also, this ladder does not have any arrangement which protects users from the danger of falling off.
U.S. Pat. No. 4,243,119 discloses a collapsible ladder without any form of burglar-proofing. It is held in position in the extended state by means of an articulated hinge. If such a ladder were to be used by several persons at the same time, the hinge at the top would be subjected to a heavy load. The risk of material failure in connection with the hinge is thus present and, if this were to occur, all the persons would find themselves stuck on the ladder as in a trap. Also this ladder lacks safety arrangements to protect users from falling off.